Cognitive functions in bipolar affective disorder and schizophrenia: comparison.
OBJECTIVE
Earlier comparisons of cognitive impairment among patients with bipolar disorder and schizophrenia have found a largely similar profile of deficits, but results have varied between studies. This prompted the current attempt at another such comparison.


METHODS
Executive functions, memory, IQ, attention-concentration and perceptuomotor function were assessed in 48 bipolar disorder patients with operationally defined euthymia, and compared with 32 schizophrenia patients in remission, and 23 normal controls. Comparisons were re-attempted after controlling for years of schooling and residual affective symptoms.


RESULTS
Uncontrolled comparisons indicated that, compared to controls, both bipolar disorder and schizophrenia patients were significantly impaired on different tests of executive function, memory, IQ and perceptuomotor functions. Controlling for years of schooling and residual affective symptoms, however, served to remove most of the differences between patients and controls, apart from some aspects of executive function in schizophrenia and memory impairment in both schizophrenia and bipolar disorder. Patients with schizophrenia consistently performed worse than patients with bipolar disorder, but none of the differences between schizophrenia and bipolar disorder were significant.


CONCLUSIONS
Patients with bipolar disorder exhibit cognitive difficulties that are very similar to schizophrenia in terms of their profile, although patients with schizophrenia may have more severe and widespread impairments. The resemblance in cognitive profiles has important implications for the etiology and treatment of both disorders.
Pradhan
Basant K
BK
Department of Psychiatry, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Chakrabarti
Subho
S
Nehra
Ritu
R
Mankotia
Anupama
A
D000328:Adult; D000339:Affect; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics; D012016:Reference Values; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology; D012959:Socioeconomic Factors; D055815:Young Adult